Initial Client/Server Communication

#1
Followed the MagicOnion quickstart guide, borrowing code from the chat sample app to get something working

Assets/Scripts/MagicOnion/AsyncLock.cs

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+using System;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace MagicOnion
+{
+    public class AsyncLock
+    {
+        readonly SemaphoreSlim semaphore;
+
+#if NON_UNITY
+        public static readonly ValueTask<LockReleaser> EmptyLock = new ValueTask<LockReleaser>(new LockReleaser(null));
+#endif
+
+        public AsyncLock()
+        {
+            this.semaphore = new SemaphoreSlim(1, 1);
+        }
+
+#if NON_UNITY
+        public async ValueTask<LockReleaser> LockAsync()
+#else
+        public async Task<LockReleaser> LockAsync()
+#endif
+        {
+            await semaphore.WaitAsync().ConfigureAwait(false);
+            return new LockReleaser(semaphore);
+        }
+
+        public struct LockReleaser : IDisposable
+        {
+            readonly SemaphoreSlim semaphore;
+
+            public LockReleaser(SemaphoreSlim semaphore)
+            {
+                this.semaphore = semaphore;
+            }
+
+            public void Dispose()
+            {
+                semaphore?.Release();
+            }
+        }
+    }
+}